html, body {
  width: 100%;
  height: 100%;
}
body {
  padding: 0;
  margin: 0;
  color: #333333;
  display: flex;
  justify-content: center;
  background-color: #50759a;
  padding-bottom: 10px;
}
#bg{
  position: fixed;
  width: 100%;
  height: 100%;
  transition: background 1.5s linear;
  background-image: url("img/bg/1.jpg");
  background-size: cover;
  background-position: center;
}
 #main{
  max-width: 800px;
  position: relative;
 }
 .box{
  background-color: rgb(255 255 255 / 80%);
  margin: 50px;
  border-radius: 20px;
  min-height: 100px;
  padding: 20px;
 }
 .center{
  text-align: center;
 }
 .img{
  display: inline-block;
  width: 200px;
  height: 200px;
  background-size: cover;
  background-position: center;
  margin: 8px;
  cursor:pointer;
  transition: 0.3s;
  box-shadow: 0 10px 20px #b9bbbe;
 }
 .img:hover {
  box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.4);
}